1、现象
2、文件结构
3、alpha.xml 定义动画
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<alpha android:fromAlpha="1.1" android:toAlpha="0.1"
android:duration="5000"/>
</set>
<!--
fromAlpha: 表示动画起始的透明度, 0.0 表示完全透明,1.0 表示完全不透明 取值在 0.0 ~ 1.0之间的 float 数据类型的数字
toAlpha: 表示动画结束的透明度,值定义同上
duration:动画持续时间,单位毫秒
-->
4、activity_main.xml 布局文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:orientation="vertical">
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:background="@drawable/test_2"
android:id="@+id/image_one_id" />
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:id="@+id/image_two_id"
android:layout_marginTop="30dp"
android:background="@drawable/test_3"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="30dp"
android:text="Aplha"
android:onClick="onClick"/>
</LinearLayout>
5、MainActivity.java 功能文件
package myapplication.lum.com.myanimation;
import android.graphics.drawable.AnimationDrawable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.view.animation.AnimationSet;
import android.view.animation.AnimationUtils;
import android.widget.ImageView;
public class MainActivity extends AppCompatActivity {
private String TAG = "LUM: ";
private ImageView imageViewOne,imageViewTwo;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imageViewOne = (ImageView) findViewById(R.id.image_one_id);
imageViewTwo = (ImageView) findViewById(R.id.image_two_id);
}
public void onClick(View view) {
//加载 xml 文件实现 动画
Animation alphaAnimation = AnimationUtils.loadAnimation(this,R.anim.alpha);
imageViewOne.startAnimation(alphaAnimation);
//代码动态实现 改变 alpha
AnimationSet animationSet = new AnimationSet(true);
AlphaAnimation alphaAnimation1 = new AlphaAnimation(1.0f,0.1f);
alphaAnimation1.setDuration(5000);
animationSet.addAnimation(alphaAnimation1);
imageViewTwo.startAnimation(animationSet);
}
}